Apparatus for cold bending of tubular bodies and the like



L. LANG 3,073,372

APPARATUS FOR COLD BENDING OF TUBULAR BODIES AND THE LIKE Jan. 15, 1963 2 Sheets-Sheet 1 Filed QOb. 22, 1958 INVENTflR:

[DA W9 Lilli L. LANG Jan. 15, 1963 APPARATUS FOR COLD BENDING OF TUBULAR BODIES AND THE LIKE 2 Sheets-Sheet 2 Filed Oct. 22, 1958 United States Patent @flice 3,033 Patented Jan. 15, 1963 3,073,372 APPARATUS FOR CGLD BENDHNG F TUEBULAR BUDEES AND THE LKKE Ludwig Lang, Michelstadt, Odenwald, Germany Filed Get. 22, 1958, Set. No. 768,9)?4 Claims priority, application Germany Get. 30, 1957 '7 Claims. (Cl. 153-38) The present invention relates to apparatus for cold bending of elongated tubular, solid cylindrical and profiled bodies, and more particularly to a portable bending machine.

it is already known to utilize in bending of tubes, rods and profiled stock a bending apparatus comprising stationary and movable bending means, and a hydraulic device for advancing the movable bending means toward the stationary means. Known bending machines of such construction invariably comprise relatively movable parts which are finished with utmost precision and thus require constant lubrication. Known apparatus are very sensitive and hence, especially when utilized at a new construction site, require constant attention and repair if a foreign body enters between the relatively movable component parts. Known bending machines also are rather bulky and require considerable space when in storage or during transportation. It is practically impossible to store such known cold bending machines, together with a set of necessary bending segments, in a crate or receptacle of reasonably small dimensions.

An important object of the present invention is to provide an extremely simple, practical, rugged and compact portable bending machine which may be reduced in size for storage and/or transportation without requiring actual dismantling of component parts.

Another object of the invention is to provide a bending machine of the above outlined characteristics which is so constructed that no foreign body can enter between precision-dimensioned component parts thereof even if the machine remains in a position ready for immediate use.

A further object of the invention is to provide a portable bending machine which may be reduced to about half its actual size for the purposes of transportation or storage.

An additional object of the instant invention is to provide a portable machine for cold bending of tubular, solid or profiled stock which is so constructed that it may be reduced in size or restored into condition for immediate use Without requiring any tools for such changes in its dimensions.

With the above objects in view, the invention resides essentially in the provision of a portable machine comprising a hydraulic motor having a cylinder and a reciprocable plunger; a source of pressure medium together with suitable control and pumping means for causing the dew of pressure medium into and for permitting the discharge of pressure medium from the cylinder; a bending frame constituting the movable bending means which is connected with and movable by the plunger; and a retractable supporting structure for the stationary bending means which latter, together with the bending frame,

rings about deformation of a workpiece placed therebetween when the plunger of the hydraulic motor is caused to perform its working stroke. The bending frame preferably comprises two pairs of carriers or plates, each pair mounting a counterbearing in the form of an adjustably installed spool, and each carrier plate is guided in its travel along the supporting structure of the stationary bending means. The latter may consist of two spaced plates which are retractable along the hydraulic motor to reduce the overall dimensions of the bending machine when the device is not in actual use. No precision is necessary in guiding the bending frame along the supporting structure toward and away from the stationary bending means.

The pumpingmeans for supplying pressure medium into the hydraulic motor preferably comprises an actusting lever which extends toward the bending Zone, ie toward the bending frame, and thus enables a single operatcr to control the bending operation and to pump the pressure medium at the same time. All controls for the pressure medium are installed in a single compact housing connected with the hydraulic motor and, when the stationary bending means together with its supporting structure is retracted toward the pump housing, the entire machine can be stored in a receptacle or crate of relatively small dimensions.

The collapsing and restoring of the bending machine is facilitated by the provision of a substantially annular member connected with the supporting structure for the stationary bending means and movable along the cylinder of the hydraulic motor between two widely spacedapart positions. In the operative position of my machine, a preferably conical surface in the annular mern ber receives a conical external zone of and abuts against a shoulder on the cylinder to maintain all parts in position for immediate use. The inclination of cooperating conical surfaces is such that no tools of any kind are required when an operator desires to collapse the machine; the annular member is merely pushed off the conical zone of the cylinder toward the pump housing.

Certain additional features of the invention reside in the provision of means for constantly urging the pump to perform one of its strokes, i.e. its suction stroke, and in the provision of resilient means for constantly urging the plunger of the hydraulic motor into retracted position when the pressure medium is free to return into its tank in the pump housing.

Other objects, advantages and attributes of my invention will become apparent by reading the following detailed description of a specific embodiment selected for illustration in the accompanying drawing, in which:

FIG. 1 is a perspective view of the improved bending machine, with a tubular workpiece shown in phantom lines in the position ready for bending;

FIG. 2 is an enlarged axial section through the hydraulic motor of my bending machine;

FIG. 3 is a fragmentary sectional View of the end portion of the hydraulic motor and a side elevational View of the bending frame connected thereto;

FIG. 4 is an enlarged section through the pump housing taken on line VI-VI of PEG. 1, as seen in the direction of the arrows; and

PEG. 5 is an enlarged section taken on line VV of FIG. 1, substantially at right angles to the sectional view of FIG. 4.

Referring now in greater detail to the drawing, and first to FIG. 1, the bending machine therein shown comprises a hydraulic motor including an elongated cylinder 1 whose rear end is connected with a housing 2 in which the control valve system, the pumping means and the receptacle for a hydraulic pressure medium are installed. Housing 2 carries a yoke 3 reciprocably supporting an actuating or pumping lever 4 provided with a knob or handgrip member 5. Lever 4 is swingably mounted in the slotted head of member 3 and is retained therein by a pivot axle 6. At its side facing the adjacent upper surface of housing 2, lever 4 is provided with a projection or nose 7 normally abutting against the head 8 of pump piston 9 which latter is permanently urged into the position of FIG. 1 by a resilient element in the form of a helical spring 10. Thus, the force exerted by an operators hand or hands upon lever 4 in the direction of arrow A and the opposing force of constantly acting spring 10 bring about reciprocating movements of pump 3 piston 9 whereby the latter causes flow of hydraulic fluid from the receptacle in housing 2 into the cylinder 1 of the hydraulic motor.

It will be noted that the handgrip member of actuating lever 4 extends toward the bending zone 11, thus enabling a workman to control the bending operation and to operate member 4 at the same time. The forward end 12 of cylinder 1 is surrounded by an annular member or ring 13 which is movable between the forward and rear ends of member 1 and is connected to the rear ends of two substantially parallel supporting plates 14a, 14b secured thereto by means of screw bolts 15. The free or forward ends of supporting members 14a, 14b are fixed to a transverse connecting member 16 by means of bolts 17. In its surface 18 which is turned toward the cylinder 1, connecting member 16 defines a recess or blind bore 19 for reception of a stud 20 forming part of, or connected with, a stationary bending member or segment 21. Thus, ring 13 with plates 14a, 14b and member 16 constitutes a supporting structure for stationary bending means 21.

The movable bending means has the form of a twin bending frame 22 which carries the counterbearings a, It is slidably mounted for travel along supporting members 14a, 1412 between the end 12 of cylinder 1 and the stationary bending means 21. Frame 22 comprises two pairs of parallel plates 22a, 22b and 22c, 22d, respectively, fixed to each other by a central connecting member 29 whose side facing the bending segment 21 is preferably given a slightly concave contour to conform to the configuration of a tubular or cylindrical workpiece which is to be deformed in my improved bending machine. Each of plates 22a-22d is formed with an elongated lug or bracket 23 sliding along the end faces 24a, 24b of members 14a, 14!), respectively, and thus guiding the bending frame 22 in its travel between the bending station 11 and bending segment 21 to prevent rotation of the counterbearings relative to the bending member 21. Counterbearings 25a, 25b are transversely spaced with respect to the axis of cylinder 1 by being mounted between plates 22a22b and 22c22d, respectively, on respective substantially vertical shafts or pivot axles 26a, 26b. The latter are retained in aligned bores or apertures 27 provided in each of plates 22a-22d by means of retaining pins 28 or the like. Due to the provision of a series of apertures 27, counterbearings 25a, 25b, in the form of rollers or spools, may be mounted at various distances from supporting plates 14a, 1412. It will be noted that members 220-2211 are symmetrical with respect to plates 14a, 14b and that they enclose an acute angle with the axis of and in a direction away from cylinder 1.

Referring to FIG. 2, cylinder 1 is rigidly connected to housing 2 by weldants 1a, and at its end 12 terminates in a reinforcing sleeve 31 which is internally threaded to receive the externally threaded bearing member or bushing 30. At its side facing the housing 2, sleeve or reinforcing member 31 defines a shoulder 32 at the larger-diameter end of a conical surface 33 which converges in the direction toward member 2. Shoulder 32 and conical surface 3 constitute stop means for the movable bending means 22-23 and 2529 to arrest the latter in a position in which the bending machine is ready for use. Plunger rod 34 is formed with a blind bore 38 which is provided with internal threads 39 at its terminal adjacent to the closed forward end 37 of member 34. The rear end 36 of bore 38 communicates with the bore 66 in cylinder 1 and is surrounded by plunger 35. Thus, member 34 is guided in bore 66 by bushing 39, on the one hand, and by its plunger 35, on the other hand. A helical spring 40 extends into the bore 38 and has its forward end threaded into the tapped portion 39. The rear or free end 41 of spring 411 extends through the open end 36 of bore 38 and is anchored in housing 2.

FIG. 3 illustrates that the bore in annular member 13 is bounded by a conical surface 42 tapering outwardly in a direction away from cylinder 1. Surface 42 is complementary to the conical surface 33 at the forward end 12 of cylinder 1 and consequently permits movements of ring 13 in a direction toward housing 2, as is indicated by arrow B. Thus, when the plunger 35 is withdrawn into the position of FIG. 2, annular member 13 with plates 14a, 14b, connecting member 16 and bending segment 21 may be withdrawn in the direction of arrow B to reduce the overall length of the bending machine considerably. The forward end 37 of plunger rod 34 is received in a bore 43 provided in central connecting member 29 and is secured thereto by a pin or screw 44. Consequently, any movements of plunger 35 and of its rod 34 in the bore 66 of cylinder 1 bring about similar movements of bending frame 22 and of connecting member 29.

The arrangement of the parts in housing 2 is illustrated in FIGS. 4 and 5. Receptacle or tank 45 for a pressure fluid or medium 46 is shown in FIG. 5. The interior of member 45 can communicate with the surrounding atmosphere through a normally open air vent valve 47 provided with an actuating member 64. A conduit 48 connects the tank 45 with a chamber 49 whose open upper end is sealed by a threaded bolt 50. The passage of pressure medium through conduit 43 is controlled by the head 52 of a valve member 53 extending from the housing 2 and provided at its free end with an actuating member in the form of a knob 54. A pressure valve 51 controls the passage of medium 46 from chamber 49 into a lower chamber or enclosure 57.

The bottom zone of receptacle 45 communicates with a chamber 55 through conduit 55a, and the chamber 55 in turn communicates with chamber 57 through a passage which is normally sealed by a suction valve 56. Depending upon the position of pressure valve 51 in chamber 49 and of suction valve 56 in chamber 57, the latter may communicate with the cylinder space 59 of pump piston 9 through a conduit or line 58. Piston 9 is guided in a sleeve 60 and passes through sealing or packing rings 61 and 62. It will be noted in FIG. 4 that the expansion spring 19 operates between the enlarged head 8 of piston 9 and the upper sealing ring 62 and thus, as above mentioned, constantly urges the pump piston in upward direction.

The operation of my improved bending machine is as follows:

If the tubular workpiece 63, shown in phantom lines in FIG. 1, is to be bent by segment 21 and counterbearing spools 25a, 25b into a shape of predetermined angularity, it is placed into abutment with the concave surface 21a of segment 21. Conduit 48 is then closed by turning the knob 54 of valve member 53. Air vent valve 47 remains open; it should be closed by its operating member 64 only when the bending machine is not in use, i.e. during transportation or storage.

Lever 4 is then reciprocated by an operator in the direction of arrow A and by spring 10 in the opposing direction. During the upward stroke of piston 9 (under the influence of resilient means 10), subatmospheric pressure is created in cylinder space 59, conduit 58 and chamber 57, whereby the pressure medium 46 is drawn from receptacle 45 through line 55a and through suction valve 56 into the enclosure 57, line 58 and cylinder space 59. During the compression stroke of piston 9 (i.e. when lever 4 moves in the direction of arrow A and displaces piston 9 by acting upon the latters head 3 against the force of constantly acting spring 10), pressure medium 46 filling chambers 57 and 59, as well as conduit 58, closes valve 56 and opens valve 51 to flow into chamber 49 and thence through line or bore 65 into the bore 66 in cylinder 1 to act against plunger 35 and displace the latter in the direction of arrow C (see FIG. 2). Spools 25a, 25b are moved into contact with workpiece 63 and cause the latter to bend about segment 21 in a direction away from the forward end of cylinder 1 and to an extent determined by the operator who actuates the lever 4.

The rear end 41 of resilient plunger-retracting spring 40 is connected to or formed with an eye or loop 67 which engages with a retaining bolt 68 anchored in housing 2. Thus, when the plunger rod 34 with plunger 35 moves in the direction of arrow C, spring is expanded and, upon release of pressure medium 46 from the cylindrical space 66 in cylinder 1, returns plunger 35 into the position of FIG. 2 together with the bending frame 22 and all parts connected therewith to permit removal of deformed workpiece 63.

To permit discharge of pressure fluid 46 from cylindrical space or bore 66, knob 54 of valve member 53 is turned by hand whereby the valve head 52 opens conduit 48 and the spring 40 is free to move plunger rod 34 with plunger 35 in the direction of arrow D (see FIG. 5). Pressure medium 46 flows through bore 65 into chamber 49 and through open conduit 48 back into the receptacle 45.

When the bending machine is moved to a new location or crated for shipment, air vent valve 47 is closed by actuating member 64 to prevent escape of pressure medium from housing 2. Surface 42 of annular member 13 is then pushed off conical surface 33 and away from abutment with shoulder 32 in the direction of arrow B (see FIG. 3) together with supporting members 14a, 14b, transverse connecting member 16, and bending segment 21. This shortens the bending machine considerably without, however, rendering it necessary to take the component elements apart. The machine may be stored or crated in relatively small receptacles or spaces and may be restored into condition for use merely by opening air vent valve 47 and by pushing annular member 13 toward the end 12 of cylinder 1, i.e. into abutment with shoulder 32.

Although one specific embodiment of my invention has been illustrated and described, it is to be understood that I am not to be limited thereto or thereby because various changes and modifications within the spirit of the invention will readily occur to persons skilled in the art. All such changes and modifications are intended to be comprehended within the meaning and range of equivalence of the following claims.

What I claim is:

1. A bending machine comprising, in combination: an elongated cylinder having a forward end and a rear end; a plunger reciprocably received in and having a rod extending toward the forward end of said cylinder; a housing connected to the rear end of the cylinder; a supply of pressure fluid in said housing; pump means carried by the housing and comprising lever means for pumping the pressure fluid into, and for thereby displacing the rod in an outward direction beyond the forward end of, said cylinder; a supporting structure including a substantially annular member slidably mounted on said cylinder for movement between the ends of said cylinder; stop means for arresting the annular member at the forward end of said cylinder; first bending means including a bending member connected with said supporting structure and reciprocable by the latter between an operative position when the annular member is arrested by said stop means and a retracted position when the annular member is adjacent to the rear end of said cylinder; and second bending means comprising two transversely spaced counterbearings connected with said rod for outward movement toward the bending member when the latter is in said operative position and the lever means is operated to bring about outward displacement of said rod beyond the forward end of the cylinder, whereby a workpiece inserted between said bending member and said counter-bending is bent about the bearing member in a direction convexly away from the forward end of said cylinder.

2. A bending machine as set forth in claim 1, wherein annular member has a bore bounded by a conical surface tapering outwardly in a direction toward the forward end of said cylinder, and wherein said stop means comprises a shoulder and an outer conical surface on said cylinder, said last mentioned surface being adjacent to said shoulder, tapering inwardly toward said rear end of said cylinder, and received in the bore of said annular member when the latter is moved toward the forward end of said cylinder.

3. The structure as set forth in claim 1, wherein said lever means extends from the rear end toward the forward end of said cylinder.

4. The structure as set forth in claim 1, further comprising resilient means connected with said plunger and anchored in said housing for constantly urging the plunger toward the rear end of said cylinder whereby said rod entrains the second bending means into the proximity of the forward end of said cylinder when the pressure fluid is free to return from the cylinder into said housing.

5. The structure as set forth in claim 1, wherein said supporting structure further comprises a pair of parallel supporting plates each having a first end and a second end with said annular member connected to the first ends of said supporting plates, and a transverse member for connecting the second ends of said plates, said bending member being connected with said transverse member and facing the forward end of said cylinder.

6. The structure as set forth in claim 1, wherein said second bending means further comprises a frame including two pairs of symmetrically disposed plates, each pair of said plates mounting a counterbearing therebetween.

7. The structure as set forth in claim 6, wherein said second bending means further comprises a central connecting member fixed to said rod and each of said plates comprises at least one lug adjacent to and slidable along said supporting structure for preventing rotation of the counterbearings with respect to said bearing member.

References Cited in the file of this patent UNITED STATES PATENTS 1,964,550 Abramson et al June 26, 1934 2,382,266 Sirnonsen Aug. 14, 1945 2,596,462 Ball May 13, 1952 2,807,438 Frank Sept. 24, 1957 2,938,564 Rhodes May 31, 1960 FOREIGN PATENTS 2,482 Great Britain Jan. 30, 1902 6,446 Great Britain Mar. 18, 1909 719,304 France Feb. 4, 1932 764,476 France May 22, 1934 1,001,604 France Feb. 26, 1952 1,025,005 France Apr. 9, 1953 

1. A BENDING MACHINE COMPRISING, IN COMBINATION: AN ELONGATED CYLINDER HAVING A FORWARD END AND A REAR END; A PLUNGER RECIPROCABLY RECEIVED IN AND HAVING A ROD EXTENDING TOWARD THE FORWARD END OF SAID CYLINDER; A HOUSING CONNECTED TO THE REAR END OF THE CYLINDER; A SUPPLY OF PRESSURE FLUID IN SAID HOUSING; PUMP MEANS CARRIED BY THE HOUSING AND COMPRISING LEVER MEANS FOR PUMPING THE PRESSURE FLUID INTO, AND FOR THEREBY DISPLACING THE ROD IN AN OUTWARD DIRECTION BEYOND THE FORWARD END OF, SAID CYLINDER; A SUPPORTING STRUCTURE INCLUDING A SUBSTANTIALLY ANNULAR MEMBER SLIDABLY MOUNTED ON SAID CYLINDER FOR MOVEMENT BETWEEN THE ENDS OF SAID CYLINDER; STOP MEANS FOR ARRESTING THE ANNULAR MEMBER AT THE FORWARD END OF SAID CYLINDER; FIRST BENDING MEANS INCLUDING A BENDING MEMBER CONNECTED WITH SAID SUPPORTING STRUCTURE AND RECIPROCABLE BY THE LATTER BETWEEN AN OPERATIVE POSITION WHEN THE ANNULAR MEMBER IS ARRESTED BY SAID STOP MEANS AND A RETRACTED POSITION WHEN THE ANNULAR MEMBER IS ADJACENT TO THE REAR END OF SAID CYLINDER; AND SECOND BENDING MEANS COMPRISING TWO TRANSVERSELY SPACED COUNTERBEARINGS CONNECTED WITH SAID ROD FOR OUTWARD MOVEMENT TOWARD THE BENDING MEMBER WHEN THE LATTER IS IN SAID OPERATIVE POSITION AND THE LEVER MEANS IS OPERATED TO BRING ABOUT OUTWARD DISPLACEMENT OF SAID ROD BEYOND THE FORWARD END OF THE CYLINDER, WHEREBY A WORKPIECE INSERTED BETWEEN SAID BENDING MEMBER AND SAID COUNTERBENDING IS BENT ABOUT THE BEARING MEMBER IN A DIRECTION CONVEXLY AWAY FROM THE FORWARD END OF SAID CYLINDER. 